Ultraviolet absorbing filters



Patented Apr. 8, 1969 3 437 483 compounds have to meet certain conditions. For exam- ULTRAVIOLET ORBING FILTERS ple, the gltraviolet absorbing compounds must not under- Fritz Nittel, 'Cologne-Stammheim, Heinz Meckl, Colognego any c ange upon color phptographlc processing should Flmard and Walter Pfischel and Hans Ulrich Levep have no tendency to crystallization and exudation, should kusen, Germany, aSsignm-s to A f Akfl g u h ft 5 have good light fastness and should also withstand the Leverkusen, Germany, a corporation of Germany temperatures of high glaze drying without being damaged.

Filed July 21, 1964, Ser. No. 384,154 It is an object of the present invention to provide ultra- Claims P 8, application y, Jilly 1963, violet absorbing compounds which in particular absorb A ,729 light of those wavelength by which the dye fading and U 8 Cl 96 84 Gosc 1/84 7 Cl 10 yellowing is primarily caused. Another is to provide ultraaims violet absorbing filter layers whlch in particular are applied onto color photographs in multilayer photographic materials. Other objects will become apparent from a ABSTRACT OF THE DISCLOSURE consideration of the following description and examples.

Color photographic layers and other materials are We now have found that ultraviolet absorbing comprotected against ultraviolet light by layer of gelatin conpounds of the following formula can be used, in particutaining a compound lar for a filter coating on color photographs to prevent dye as defined below. fading and discoloration and to overcome the aforementioned difficulties without any deleterious effect of the ultraviolet absorbing compounds itself;

RI! N N 5 R-X-CH2CH20\ CH2CHCHZO\ Y /nl I jm-I This invention relates to ultraviolet absorbing filters for wherein:

protection against the harmful effect of ultraviolet radia- R represents a hydrogen atom a Straight chain or branched tion, in particular to photographic elements containing alkyl group with 20. carbon atoms, an alkenyl group the ultraviolet absorblng filter. having up to carbon atoms with nonconjugated car- It is known that certain materials are adversely affected hon-carbon double bonds Such as n oleyl, phenyl, by ultraviolet radiation, when such materials are exposed d alkaryl h as phenyl Substituted with alkyl radito daylight. In order to protect these materials against the cals having up to 20 carbon atoms, or aralkyl such as ultraviolet radiation it is common practice to provide benzyl or phenylethyl; them with a protective coating containing an ultraviolet R represents a hydrogen atom or alkyl, preferably lower absorbing compound. alkyl having up to 3 carbon atoms, such as methyl or This is especially true in the case of color photographic y images in multilayer photographic materials where the TePTeSeQtS a hydrogen atom, y Preferably lower dye images formed in the light-sensitive layers by color alkyl havmg up to 3 carbon atoms, such as methyl or development are susceptible to fading and discoloration ethyl or arY1SuchasPhfinylornaphthyl;

by the action of ultraviolet light to which the photo- Xrepresems R graphic images are subjected during viewing in daylight. I It is advantageous to apply the ultraviolet absorption compounds in separate layers since, if they are incorporated into the dye images containing layers, very often the opposite etfect is produced, namely intensified fading of the dye images It is common Practice to apply the may be esterified preferably with lower aliphatic alcoultraviolet absorbing layer either on the unexposed and holshaving up to 5 carbon atoms, or a group of the unprocessed photographic material or on the processed 60 formula:

color photographic material containing the dye images.

Y represents hydrogen, halogen such as chlorine or bromine, hydroxy, etherified hydroxy preferably alkoxy having up to 5 carbon atoms, sulfo, carboxyl which In particular if the filter layers are applied onto the un- 2C 20/n 1 CHz-(fHCHzO processed photographic element, the ultraviolet absorbing OH n represents an integer from 110; m represents an integer from 1-2, at least it or m representing an integer larger than 1.

The use of compounds of the above aromatic azine type as ultraviolet absorbing compounds is known from British patent specification No. 591,275, but the compounds mentioned therein are of limited utility in particular if utilized in protective coatings on color photographs. The compounds described in the above specification have high melting points, a high tendency to crystallization and low solubility in the solvents used in the emulsification process in order to incorporate them into the hydrophilic colloid layers. Thus, it is hardly possible to produce ultraviolet absorbing coatings therewith.

The ultraviolet absorbing compounds to be used according to the present invention represent crystalline or waxy substances or highly viscous oils of very good solubility and excellent emulsifiability. The compounds are distinguished by high molar extinction, good light stability and a decay of absorption at the boundary of the visible spectral region (see the accompanying drawings). On account of their good emulsifiability, they can be introduced into the photographic layers in the form of emulsions without any difficulty. For the preparation of the emulsions, it is possible also to use high-boiling organic solvents, such as phosphoric acid esters or esters of polybasic carboxylic acids such as phthalic or adipic acid. The highly viscous ultraviolet absorbing compounds introduced in the form of emulsions into the photographic layers are further distinguished by the fact that they increase considerably the flexibility of the photographic gelatin layer and thus prevent these layers becoming brittle, particularly with low air humidity.

The use of the compounds is not restricted to color photographic purposes; it can also be extended to any desired other fields of use, such as plastic foils, light filters and packing materials.

The ultraviolet absorbing compounds of the present invention can be prepared by reacting -chloropropyleneglycol ethers or chlorinated ethylene oxides with hydroxybenzaldehyde or hydroxyphenones and condensing the resulting aldehydes or ketones with hydrazine.

The following examples will serve to illustrate the manner whereby the ultraviolet absorbing compounds can be prepared.

(Ia) -Chloropropylene glycolethers These compounds are produced by reacting epichlorhydrine with alcohols to form compounds of the following formula:

RO.CH2CH.CH2C1 In the above reaction it might be possible that also small amounts of the isomeric compounds of the following formula are produced:

The method is illustrated by the following specific example.

' -Chloropropylene glycol-a-octylether n-CsHi7-O-CHzCHCHzCl 500 g. of n-octanol and ml. of SnCL; are heated to 80 C. and

380 g. of epichlorhydrine are added dropwise with stirring and at such a speed that the internal temperature is kept at 110 C. After completing the addition, the temperature is kept for another hour at 80 C. and then the mixture is distilled under high vacuum. 725 g. of an oil with a B.P. 0.1=110 C. are Obtained.

The following 'y-chloropropylene glycol-ethers are prepared in analogous manner:

H b.p. 0.1; 133 C.

b.p. 0.1; C.

OH b.p. 0.1 180 C.

H3 CH3 H b.p. 0.1 200 0. (lb) Chlorinated ethyleneoxides and ethers thereof Ethers of ethyleneoxides are prepared in known manner by reacting the desired alcohol with the ethyleneoxides.

The glycol ethers thus obtained are transformed by bolllng with excess thionyl chloride into the chlorides CnH (OCH CH Cl for example the following compound 1z z5( z 2)4.

(Ic) Ethyleneglycolethers of 'y-chloropropyleneglycol can be prepared by reacting the polyethyleneglyol or the monoethers thereof with epichlorhydrine as described under Ia (II) Reaction of hydroxybenzaldehyde or hydroxyphenones with 'y-chloropropyleneglycolethers or chloronated ethylene glycols A suitable method is illustrated by way of the following preparation of a compound having the formula:

30 g. of sodium are dissolved in 400 ml. of absolute methanol,

g. of 4-hydroxybenzaldehyde,

300 g. of y-chloropropylene glycol-n-octyl ether and 1 g. of NaI are added and the mixture boiled for 12 hours under reflux. The pH is adjusted to 6 with If the octylether is replaced by the corresponding octadecylether, the following compound with a melting point of 71 C. is obtained:

Other aldehydes of the above type are obtained in analogous reactions.

Hydroxyphenones, for example the 4-hydroxyacetophenone are reacted under similar conditions to form ketones of the following general formula:

Polyglycol derivates are obtained accordingly.

CH3 (III) Ultraviolet absorbing azine compounds The aldehydes or ketones prepared as described under 11 can be reacted without further purification with hydrazine to form the ultraviolet absorbing compounds of the present invention.

(A) Symmetrical azines The preparation of the compounds is shown by the following specific example:

100 g. of the following compound:

and 4 g. of hydrazine hydrate are refluxed for 1 hour in 100 ml. of ethyl alcohol, 2 ml. of glacial acetic acid and 0.5 ml. of a 10% aqueous sodiumacetate solution. After adding another 4 g. of hydrazine hydrate, heating is continued for another 30 minutes, the mixture is then introduced into water, suction-filtered and recrystallized from methanol.

Yield of Compound 4 (as listed below) is 75% (75 g.). Azines which carry branched fatty acid radicals are usually obtained in the form of highly viscous oils. In these cases, the procedure is modified as follows: after completing the reaction, the reaction mixture is treated with activated carbon or bleaching earth, introduced into water, extracted with CH Cl and the solvent is distilled olf. In this way, the substances are obtained in a sufficiently pure form. Their characterisation is efiected by their infrared and ultraviolet spectra (7\ max.: 330 m Suitable compounds are, for example:

Ha H

light yellow crystals M.P. 210 C.

CH2 H yellow waxy substance CH3 H highly viscous yellow oil light yellow crystals M.P. 87 C.

CgHs H yellow waxy substance H; OH

highly viscous yellow oil CH3 H highly viscous yellow oil light yellow crystals M.P. 97 C.

light yellow crystals M.P. 99 C.

highly viscous yellow oil colorless crystals, M.P. 101 C.

light yellow crystals, M.P. 172 C.

7 8 14) of Compound 10 dissolved in 50 ml. of ethyl acetate and [nCl2 25(O H2CII2)4O CH=N ]2 further processed as in Example 1. The improvement in the light fastness is similar to that of Example 1. highly viscous yellow 011 3 EXAMPLE 3 (B) Unsymmetrical azines 760 ml. of aqueous elatin solution and 60 ml. By reactmg the PIFVIOHSIY descnbed aldehydes Wlth of a 10% aqueous solution 0% saponine as emulsifier are hydrazones of aromatic aldehydes or ketones, unsymmetmixed in the manner referred to in Example 1 with ncal azmes are i of Compound 3 dissolved in 50 ml. of ethyl acetate, and

The method 1s illustrated by the following specific exfurther Processed as in Example 1. ample: 10 The ultraviolet absorber layers obtained in accordance 95 g. of the following compound with the above examples are completely clear, withstand the color processing without any change and do not show n-CrsHa7-O-OH2C]I-CHzO-CHO any exudation phenomena under high glaze drying. No D 15 precipitation occurs during the storage of the aqueous meltmg heated emulsions. and g. of salicylaldehyde hydrazone are boiled for 1 EXAMPLE 4 hour under reflux in 400 ml. of alcohol, 2 cc. of glacial A color photographic image in a processed multilayer acetic acid and 0.5 ml. of sodium acetate solution, cooled, film or paper strip is coated with an ultraviolet absorbing suction-filtered and recrystallized from methanol. 20 layer as described in Example 1. Measuring of the coated Yield of ultraviolet absorbing Compound 15: 52%. element indicates a considerable density to ultraviolet In the same manner, hydrazones of aromatic aldehydes light. The light fastness of the color photograph is imor ketones with other substituents such as H, Cl, proved by the factor 10 as compared with a color photo- OCH etc. can be reacted. graph of the same type without a protective layer. The

The application to photographic elements is shown in thickness of the layer is about 3 1.. the following examples: If applied in form of a protective layer, the thick- EXAMPLE 1 ness of that layer is preferably between 1 and 10 more 30 preferably between 1 and 5a. The layer may contain be- 760 ml. of 10% q o gelatln 801M101! and tween 5 and by weight of the ultraviolet absorbing of a 10% aqueous solution of dodecyl benzene sulfonate compounds based on the weight of the dried layer.

as emulsifier are vigorously stirred in an emulsifying appa- W laim;

ratus and the solution consisting of 20 g. of Compound 1. A photographic element comprising at least one 7 dissolved in 50 ml. of ethyl acetate, is slowly added. 40 supported photographic silver halide emulsion layer and The mixture is stirred for 15-20 minutes. After cooling, a gelatin layer containing an effective amount up to the the solidified mass is formed into noodles and dried. The weight of the gelatin of an ultraviolet absorbing comdried emulsion is completely clear. It is applied in the pound of the following formula:

I C=N-N=O RX OH2CHzO (oHr-oHoHz0 Y j -1 ()H /m--! form of a 2-5% aqueous solution as a protective layer wherein: onto a light-sensitive multilayer color photographic mate- R represents hydrogen, alkyl having up to 20 carbon timeliness: atoms, olefinically unsaturated alkyl having up to 20 A solution suitable for casting can also be prepared by carbon atoms phenyl benzyl or Phenyl ethyr diluting the 10% emulsion to a 2-5% solut1on instead of stands for hgdrogenbr alkw drying it. Alternatively, in the emuls1fy1ng operation a represents hydrogen alkyl phenyl or naphthy1 2-5% gelatin solution may be used. X represents 0 or The example F be fi i Such a Way that to Y represents hydrogen, halogen, hydroxy, etherified hy- 50% of the welght of gelatm 1S replaced the utra' droxy, sulfo, carboxyl or a radical of the following violet absorbing compound. formula:

After usual color-forming processing of the photographic material, images are obtained in which the light fastness is improved by a factor of 2-10, depending on f the layer thickness and concentration of the ultraviolet 2CHZO I (om-( 11101120 l absorbing compound. 0H

The improvement in the fastness is determined by an image with an ultraviolet protective layer and an image with a pure gelatin protective layer being exposed until the same degree of fading is reached. The ratio of the Lux n is an integer from 1-10, and m is an integer from l-2, at least one of the integers being larger than 1 and the compound is viscous at ordinary hours required gives the improvement factor. t t

empera ures. EXAMPLE 2 2. A photographic element as defined in claim 1, 760 ml. of 10% aqueous gelatin solution and 60 ml. of wherein a 10% aqueous solution of saponine as emulsifier are X represents oxygen;

mixed in the manner referred to in Example 1 with 20 g. R an alkyl group having up to 20 carbon atoms;

9 10 R and R" each represents hydrogen; and violet radiation, each emulsion layer containing a coupled- Y is a group of the following formula: dye image subject to fading being arranged between said support and a protective gelatin layer containing an effec- RX\CHzCHzO/ (CHz-CHCHzOT tive amount up to the weight of the gelatin of an ultra- 5 violet absorbing compound of the following formula:

-C NN(' R-X-OHzCH20 CHzCHCHzO Y /u-1 H m-l wherein:

3. A supported ultraviolet absorbing gelatin filter layer containing an effective amount up to the weight of the gelatin of an ultraviolet absorbing compound of the following formula:

R represents hydrogen, alkyl having up to carbon atoms, olefinically unsaturated alkyl having up to 20 carbon atoms, phenyl, benzyl or phenyl ethyl;

R stands for hydrogen or alkyl;

RI! 6 N N R-x omomo CHz-CHCHzO Y /n-1 (gH 'R" represents hydrogen, alkyl, phenyl or naphthyl; R represents hydrogen, alkyl having up to 20 carbon X represents 0 or S;

atoms, olefinically unsaturated alkyl having up to 20 Y represents hydrogen, halogen, hydroxy, etherified hycarbon atoms, phenyl, benzyl or phenyl ethyl; droxy, sulfo, carboxyl or a radical of the following R stands for hydrogen or alkyl; formula: represents hydrogen, alkyl, phenyl or naphthyl; H2CH2O\ (CHPCHCHZCQ X represents 0 or S;

jm-l Y represents hydrogen, halogen, hydroxy, ethen'fied hy- $11 droxy, sulfo, carboxyl or a radical of the following nis aninteger from 1-10, and formula: m is an integer from 1-2, at least one of the integers is larger than 1 and the compound is viscous at ordinary temperatures.

( A photographic element as defined m clami 5, where- X represents oxygen;

R an alkyl group having up to 20 carbon atoms;

R and R" each represents hydrogen and Y is a group of the following formula:

n is an integer from 1-10, and m is an integer from 1-2, at least one of the integers 1s OHPCHCHZO\ larger than 1 and the compound 1s VlSCOUS at ordinary /n1 g /m-1 temperatures. H 4. A supported ultraviolet absorbing filter layer as A p f p elemfint as defined in clalm Wheredefin d i l im 3, wh i in the support [8 a paper support. X represents oxygen; R an alkyl group having up to 20 carbon atoms; References Clted R and R" each represents hydrogen; and UNITED STATES PATENTS Y 15 a group of the followmg formula? 2,605 333 1952 (Hickman 5 FOREIGN PATENTS 591,275 8/ 1947 Great Britain. RX -CHzCHzO- onr-onomo OTHER E ERENCES H Schwartz, A. M. et aL, Surface Active Agents Their Chemistry and Technology, 1949, pp. 202-203.

NORMAN G. TORCHIN, Primary Examiner.

5. A color photographic element comprising a support RONALD E SMITH, Asslstant Examine"- having thereon a plurality of photographic emulsion layers U S C1 X R containing coupled-dye images at least one of said dye images being subject to fading by the action of ultra- 117-33.3; 252300 

